中文摘要：

本文研究变频微波和水浴两种低温加热方式对牛肉加热过程中嫩度、保水性和微生物杀死率的影响。以牛大腿腱子肉为实验材料,在两种低温加热方式下经不同加热温度和加热时间处理后,检测肉品各项指标。结果表明：微波加热时间短;微波加热温度每降低5℃,加热时间缩短且节能10%~15%。微波加热牛肉的肉汁渗出率明显小于水浴加热。两种加热方式下牛肉的剪切力都是随加热温度的升高呈波浪形趋势;加热温度为60℃时,剪切力达到最大值,继续升高到65℃,剪切力为最小值。微波加热牛肉的剪切力小于水浴加热;当微波加热温度为65℃保温4~6 min时,剪切力较小。牛肉水分保留率与肉汁渗出率密切相关,线性方程为y=-0.323x＋99.49（R2=0.927）。两种加热方式下,温度高于60℃都能杀死99%以上的微生物。综合分析得出结论：在变频微波500 W、控温65℃条件下加热42 g（±2）牛肉4~6 min,肉品品质较好。

英文摘要：

The effects of two low-temperature heating methods including inverter microwave heating and water bath heating on the tenderness,water-holding capacity,and sterilization rate of beef during heating were investigated in this study.The beef topside muscle was used as the experimental material,and all indicators of the meat products were determined after the treatments were carried out using two low-temperature heating methods at different temperatures and durations.The results showed that heating time using an inverter microwave was short.For every 5 ℃ reduction in microwave heating,the heating time was shortened and the electricity consumption could be saved by 10~15%.The drip loss of beef upon microwave heating was significantly less than drip loss upon water bath heating.Both shear forces of beef for the two heating methods showed a wavy trend with increasing temperature;the maximum shear force was reached when the heating temperature was 60 ℃,and the minimum shear force was reached when the heating temperature continuously increased to 65 ℃.The shear force of beef upon microwave heating was less than the shear force after water bath heating.When the beef sample was microwave-heated at 65 ℃ for four to six minutes,the shear force of beef was relatively low.The water holding capacity of beef was closely related to its drip loss,and this relationship could be expressed by the linear equation y=-0.323x＋99.49（R2 = 0.927）.In both heating methods,over 99% of microorganisms could be eliminated when the heating temperature was over 60 ℃.In conclusion,good beef quality could be obtained after 42（±2） g of beef was heated by a 500 W-inverter microwave at 65 ℃ for four to six minutes.